This chapter focuses on the performance enhancement brought by the addition of caching capabilities to full-duplex (FD) radios in the context of ultra-dense networks (UDNs). In particular we aim at showing that the interference footprint of such networks, i.e., the major bottleneck to overcome to observe the theoretical FD throughput doubling at the network level, can be significantly reduced thanks to edge caching. A caching model is designed to mimic a geographical caching policy based on the popularity of local files and to compute their associated cache-hit probability. Subsequently, we calculate the probability of successful transmission of a file requested by a use equipment, either directly by its serving small cell base station (SCBS) or by the corresponding backhaul node (BN): this quantity is then used to lower-bound the throughput of the considered network. Our approach makes use of tools from stochastic geometryto guarantee the generality of our results and analytical tractability of the problem.

Full duplex ultra-dense network (FDUDN) is envisioned as a promising network paradigm for spectrum efficiency enhancement. This chapter presents a power management scheme, which maximizes the total capacity of FDUDN, under given Quality-of-Service (QoS) and cross-tier interference constraints. The inter-cell power control is formulated as a non-convex optimization problem and the variable substitution is used to transform it into a convex one. Furthermore, the problem is solved through a low-complexity heuristic scheme, which utilizes the water-filling theorem in inter-cell power allocation. Simulation demonstrates the enhancement effect of the proposed scheme in terms of the capacity and the power efficiency.

The network densification is one of the prominent solutions for fifth-generation (5G) networks to utilize spectrum resources through intensive deployment of small cells. However, the traffic management in dense networks become a serious challenge for underlying infrastructure supporting the virtual core network. Moreover, 5G will employ different types of communication frameworks: ultra-reliable low latency communication (URLLC), enhanced Mobile Broadband (eMBB), and massive Internet of Things (mIoT). Each identify standard slice type (STT) that have different performance requirements and enabling technologies. The current network developers do not provide any concise identification on how those logic networks would be administrated on top of physical network. This chapter investigates the 5G sliced networks and study virtual networking options to meet the performance requirements of service-based architecture.

This chapter studies the potential of physical layer security in future ultra-dense networks. The unique features of ultra-dense networks are summarized, which can be exploited to enhance the secure transmission at the physical layer. We illustrate that physical layer security can be implemented in many use cases such as vehicle-to-everything, edge computing and caching services, to safeguard the confidential messages. The opportunities and challenges in these research areas are presented.